Finally finished and blocked the filet crochet curtain and hung it in the bathroom:
Pattern: Bernat Blocks Curtain (The pattern is free but you need to register with the site to view/download it.)
Yarn: Coats & Clark Royale Classic Crochet Thread, Size 10, Ecru colorway
Hook: 1.75 mm
Notes: As you can see, it's not quite wide enough. I'm not really bothered but someone on Ravelry made a nice suggestion that I might try: get some sheer fabric from Joann's and drap a narrow piece over the bar at either end. The should fill in the gaps.
I opted not to crochet loops across the top. Instead, I simply got ring clips (about $7 for a package 6) and a tension rod.
I really do like how this turned out.
And it's a vast improvement from what was there- a pillowcase clipped to the window locks with clothespins. For a year.